package cn.com.flever.netty;

import cn.com.flever.handler.AbstractHandler;
import cn.com.flever.handler.MobileHandler;
import cn.com.flever.handler.PCHandler;
import cn.com.flever.utils.EncryptionUtils;
import com.alibaba.fastjson.JSONObject;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.*;
import io.netty.handler.codec.http.DefaultFullHttpResponse;
import io.netty.handler.codec.http.FullHttpRequest;
import io.netty.handler.codec.http.HttpResponseStatus;
import io.netty.handler.codec.http.HttpVersion;
import io.netty.handler.codec.http.websocketx.*;
import io.netty.util.CharsetUtil;
import lombok.extern.slf4j.Slf4j;

import java.lang.reflect.Method;
import java.time.LocalDateTime;
import java.util.HashMap;

import static io.netty.handler.codec.http.HttpHeaderUtil.isKeepAlive;

@Slf4j
public class NettyHandler extends SimpleChannelInboundHandler<Object> {

    private WebSocketServerHandshaker handshaker;

    private static HashMap<String, AbstractHandler> handlerMap=new HashMap<>();

    static {
        handlerMap.put("pc", new PCHandler());
        handlerMap.put("mobile", new MobileHandler());
    }

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        log.debug("收到消息："+msg);
        if (msg instanceof FullHttpRequest){
            //以http请求形式接入，但是走的是websocket
            handleHttpRequest(ctx, (FullHttpRequest) msg);
        }else if (msg instanceof WebSocketFrame){
            //处理websocket客户端的消息
            handlerWebSocketFrame(ctx, (WebSocketFrame) msg);
        }
    }

    @Override
    protected void messageReceived(ChannelHandlerContext channelHandlerContext, Object o) throws Exception {

    }

    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        //添加连接
        log.debug("客户端加入连接："+ctx.channel());
        ChannelSupervise.addChannel(ctx.channel());
    }

    @Override
    public void channelInactive(ChannelHandlerContext ctx) throws Exception {
        //断开连接
        log.debug("客户端断开连接："+ctx.channel());
        ChannelSupervise.removeChannel(ctx.channel());
    }

    @Override
    public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
        ctx.flush();
    }

    /**
     * 处理websocket消息
     * @param ctx
     * @param frame
     */
    private void handlerWebSocketFrame(ChannelHandlerContext ctx, WebSocketFrame frame){
        // 判断是否关闭链路的指令
        if (frame instanceof CloseWebSocketFrame) {
            handshaker.close(ctx.channel(), (CloseWebSocketFrame) frame.retain());
            return;
        }
        // 判断是否ping消息
        if (frame instanceof PingWebSocketFrame) {
            ctx.channel().write(
                    new PongWebSocketFrame(frame.content().retain()));
            return;
        }
        // 本例程仅支持文本消息，不支持二进制消息
        if (!(frame instanceof TextWebSocketFrame)) {
            log.debug("本例程仅支持文本消息，不支持二进制消息");
            throw new UnsupportedOperationException(String.format("%s frame types not supported", frame.getClass().getName()));
        }
        // 返回应答消息
        String request = ((TextWebSocketFrame) frame).text();
        JSONObject res=null;
        try{
            //解密消息
            request= EncryptionUtils.decrypt(request);
            JSONObject req=JSONObject.parseObject(request);
            //根据类型调用handler
            String type=req.getString("type");
            AbstractHandler handler = handlerMap.get(type);
            //handler派发
            res=handler.dispacher(req, ctx.channel());

        }catch (Exception e)
        {
            log.error("解密失败");
        }
        if(res!=null)
        {
            TextWebSocketFrame tws = new TextWebSocketFrame(res.toJSONString());
            // 群发
            //ChannelSupervise.send2All(tws);
            // 返回【谁发的发给谁】
            ctx.channel().writeAndFlush(tws);
        }
    }

    /**
     * 唯一的一次http请求，用于创建websocket
     * @param ctx
     * @param req
     */
    private void handleHttpRequest(ChannelHandlerContext ctx,
                                   FullHttpRequest req) {
        //要求Upgrade为websocket，过滤掉get/Post
        if (!req.decoderResult().isSuccess()
                || (!"websocket".equals(req.headers().get("Upgrade")))) {
            //若不是websocket方式，则创建BAD_REQUEST的req，返回给客户端
            sendHttpResponse(ctx, req, new DefaultFullHttpResponse(
                    HttpVersion.HTTP_1_1, HttpResponseStatus.BAD_REQUEST));
            return;
        }
        WebSocketServerHandshakerFactory wsFactory = new WebSocketServerHandshakerFactory(
                "ws://localhost:8081/websocket", null, false);
        handshaker = wsFactory.newHandshaker(req);
        if (handshaker == null) {
            WebSocketServerHandshakerFactory
                    .sendUnsupportedVersionResponse(ctx.channel());
        } else {
            handshaker.handshake(ctx.channel(), req);
        }
    }


    /**
     * 拒绝不合法的请求，并返回错误信息
     * @param ctx
     * @param req
     * @param res
     */
    private static void sendHttpResponse(ChannelHandlerContext ctx,
                                         FullHttpRequest req, DefaultFullHttpResponse res) {
        // 返回应答给客户端
        if (res.status().code() != 200) {
            ByteBuf buf = Unpooled.copiedBuffer(res.status().toString(),
                    CharsetUtil.UTF_8);
            res.content().writeBytes(buf);
            buf.release();
        }
        ChannelFuture f = ctx.channel().writeAndFlush(res);
        // 如果是非Keep-Alive，关闭连接
        if (!isKeepAlive(req) || res.status().code() != 200) {
            f.addListener(ChannelFutureListener.CLOSE);
        }
    }
}